Android运行时权限不可访问

Question

当我在设备中自动安装应用程序时，我正在尝试在 android 中设置位置权限设备将位置权限分配给应用程序(使用 ManifestFile)。如果我手动禁用该位置的权限并再次运行该应用程序，它不会显示任何弹出窗口(我编程询问)。

private const int LOCATION_GROUP_PERMISSION_REQUEST = 1;
if ((int)Build.VERSION.SdkInt > 22) {
            if (ContextCompat.CheckSelfPermission (this, Android.Manifest.Permission_group.Location) != Android.Content.PM.Permission.Granted) {
                Toast.MakeText (this, "Something Really wrong", ToastLength.Short).Show ();
                var data = ActivityCompat.ShouldShowRequestPermissionRationale (this, Manifest.Permission_group.Location);
                if (!data) {
                    AlertDialog.Builder builder;
                    builder = new AlertDialog.Builder (this);
                    builder.SetTitle ("Location Permission is Disabled");
                    builder.SetMessage ("Location permission is needed ");
                    builder.SetCancelable (false);
                    builder.SetPositiveButton ("Enable", delegate {
                        ActivityCompat.RequestPermissions (this, new String [] { Manifest.Permission_group.Location },
                                                       LOCATION_GROUP_PERMISSION_REQUEST);
                    });
                    builder.Show ();
                } else {

                    ActivityCompat.RequestPermissions (this, new String [] { Manifest.Permission_group.Location },
                                           LOCATION_GROUP_PERMISSION_REQUEST);
                }

            } else {
                GoToActivity ();
            }
        }

数据变量总是返回false

        public override void OnRequestPermissionsResult (int requestCode, string [] permissions, Android.Content.PM.Permission [] grantResults)
    {

        if (requestCode == LOCATION_GROUP_PERMISSION_REQUEST) {

            for (int i = 0; i < permissions.Length; i++) {
                if (grantResults [i] == Android.Content.PM.Permission.Granted) {
                    Toast.MakeText (this, "Param granted", ToastLength.Short).Show ();
                } else if (grantResults [i] == Android.Content.PM.Permission.Denied) {
                    Toast.MakeText (this, "param Denied", ToastLength.Short).Show ();
                }
            }
        } else {
            base.OnRequestPermissionsResult (requestCode, permissions, grantResults);
        }

    }

//权限长度为零

Answer 1

运行时权限仅来自 Api 级别 23 及以上我知道这个答案不是您问题的完美答案，我用母语回答，所以至少它可以帮助您将其转换为 xamarin。

     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
                        != PackageManager.PERMISSION_GRANTED
                        || ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                        != PackageManager.PERMISSION_GRANTED) {
                    // permissions have not been granted.
                        requestPermissions();

                } 
            }
      }


 private void requestPermissions() {

        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.ACCESS_COARSE_LOCATION)
                || ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.ACCESS_FINE_LOCATION)) {

            // Provide an additional rationale to the user if the permission was not granted
            // and the user would benefit from additional context for the use of the permission.
            // For example, if the request has been denied previously.
            // this is my custom dialog change as per ur requirement to notify user
            showPermissionRationaleDialog("Locations permissions are needed to demonstrate access.", PERMISSIONS_LOCATION, false);
          //when user click ok in dialog you have to call requestForPermission method
        } else {
            // permissions have not been granted yet. Request them directly.
            requestForPermission(PERMISSIONS_LOCATION);
        }
    }

//请求生成

private void requestForPermission(final String[] permissions) {
        ActivityCompat.requestPermissions(NwSelectionActivity.this, permissions, REQUEST_CODE);
    }

//结果处理

@Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {

        if (requestCode == REQUEST_CODE) {

            if (PermissionUtil.verifyPermissions(grantResults)) {
                // All required permissions have been granted,

            } else {
                boolean showRationale = ActivityCompat.shouldShowRequestPermissionRationale(this,
                        permissions[0]);
                Log.i(TAG, "Locations permissions were NOT granted.");
                if (!showRationale) {
   //here you show dialog to user to manually enable location permission in setting
                    showPermissionRationaleDialog("Allow App to access your locations. Tap Setting > Permissions, and turn Location on.", PERMISSIONS_LOCATION, true);
                }
            }


        } else {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }